Abstract
In many field organizations, such as those in the industrial and service sectors, poor working posture is a common issue that can lead to various human body problems, particularly musculoskeletal disorders (MSDs) and physiological stress. Numerous tasks in the workplace, particularly in the industrial sector (i.e., manual material handling tasks), require an individual to perform in poor working conditions to meet task demands. The purpose of the current study was to evaluate musculoskeletal disorders and identify ergonomic factors related to lower back, shoulder and lower arm pain in two types of manual tasks: lifting and pulling objects in supermarket warehouses. A total of 92 male workers (ages 26–38) participated; 45 workers performed lifting tasks (first posture) and 47 workers performed a task that involved pulling heavy objects (second posture). Rapid Upper Limb Assessment (RULA) and a pain self-report chart were used. The heart rate (HR) was continuously recorded to evaluate the physiological stresses of each task posture. The results showed that lifting task highly significantly impacted low back pain among all participants. In addition, the results found a significant correlation existed between trunk, upper arm and lower arm scores and all self-report charts of pain and discomfort in the lower back, upper arm and lower arm region for all participants. Also, the pulling heavy object task posture significantly affected the lower arm score and reflected a highest prevalence of MSDs on wrist body part. The results presented a significant association existed between lower arm and wrist scores and all self-report charts of pain and discomfort in the lower arm and wrist body parts of all participants. The higher HR value was associated with the lifting task posture. There was a significant difference between both task postures overall. The results of the study proved that the RULA method was a useful tool to assess the MSDs on body regions in manual lifting and pulling tasks.